257 | C # program for above approach ; Function to find the nth 257 - gon Number ; Driver code
using System ; class GFG { static int gonNum257 ( int n ) { return ( 255 * n * n - 253 * n ) / 2 ; } public static void Main ( String [ ] args ) { int n = 3 ; Console . Write ( gonNum257 ( n ) ) ; } }